diff --git a/packages/server/package.json b/packages/server/package.json
index 480cb7ee2..ff06a2160 100644
--- a/packages/server/package.json
+++ b/packages/server/package.json
@@ -167,6 +167,9 @@
       "**/*.(t|j)s"
     ],
     "coverageDirectory": "../coverage",
-    "testEnvironment": "node"
+    "testEnvironment": "node",
+    "moduleNameMapper": {
+      "^@/(.*)$": "<rootDir>/$1"
+    }
   }
 }
diff --git a/packages/server/src/modules/Import/ImportFileDataTransformer.ts b/packages/server/src/modules/Import/ImportFileDataTransformer.ts
index d20df20fa..b89edd011 100644
--- a/packages/server/src/modules/Import/ImportFileDataTransformer.ts
+++ b/packages/server/src/modules/Import/ImportFileDataTransformer.ts
@@ -55,9 +55,8 @@ export class ImportFileDataTransformer {
 
   /**
    * Aggregates parsed data based on resource metadata configuration.
-   * @param {number} tenantId
-   * @param {string} resourceName
-   * @param {Record<string, any>} parsedData
+   * @param {string} resourceName - The resource name.
+   * @param {Record<string, any>} parsedData - The parsed data to aggregate.
    * @returns {Record<string, any>[]}
    */
   public aggregateParsedValues(
@@ -110,8 +109,11 @@ export class ImportFileDataTransformer {
     valueDTOs: Record<string, any>[],
     trx?: Knex.Transaction
   ): Promise<Record<string, any>[]> {
-    // const tenantModels = this.tenancy.models(tenantId);
-    const _valueParser = valueParser(fields, {}, trx);
+    // Create a model resolver function that uses ResourceService
+    const modelResolver = (modelName: string) => {
+      return this.resource.getResourceModel(modelName)();
+    };
+    const _valueParser = valueParser(fields, modelResolver, trx);
     const _keyParser = parseKey(fields);
 
     const parseAsync = async (valueDTO) => {
diff --git a/packages/server/src/modules/Import/_utils.spec.ts b/packages/server/src/modules/Import/_utils.spec.ts
new file mode 100644
index 000000000..9665e5cca
--- /dev/null
+++ b/packages/server/src/modules/Import/_utils.spec.ts
@@ -0,0 +1,287 @@
+import { aggregate } from './_utils';
+
+describe('aggregate', () => {
+  describe('basic aggregation', () => {
+    it('should aggregate entries with matching comparator attribute', () => {
+      const input = [
+        { id: 1, name: 'John', entries: ['entry1'] },
+        { id: 2, name: 'Jane', entries: ['entry2'] },
+        { id: 1, name: 'John', entries: ['entry3'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(2);
+      expect(result[0]).toEqual({
+        id: 1,
+        name: 'John',
+        entries: ['entry1', 'entry3'],
+      });
+      expect(result[1]).toEqual({
+        id: 2,
+        name: 'Jane',
+        entries: ['entry2'],
+      });
+    });
+
+    it('should preserve order of first occurrence', () => {
+      const input = [
+        { id: 2, entries: ['a'] },
+        { id: 1, entries: ['b'] },
+        { id: 2, entries: ['c'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result[0].id).toBe(2);
+      expect(result[1].id).toBe(1);
+    });
+  });
+
+  describe('no matching entries', () => {
+    it('should return all entries unchanged when no comparator matches', () => {
+      const input = [
+        { id: 1, name: 'John', entries: ['entry1'] },
+        { id: 2, name: 'Jane', entries: ['entry2'] },
+        { id: 3, name: 'Bob', entries: ['entry3'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(3);
+      expect(result).toEqual(input);
+    });
+  });
+
+  describe('edge cases', () => {
+    it('should return empty array when input is empty', () => {
+      const result = aggregate([], 'id', 'entries');
+
+      expect(result).toEqual([]);
+      expect(result).toHaveLength(0);
+    });
+
+    it('should return single entry unchanged when input has one item', () => {
+      const input = [{ id: 1, name: 'John', entries: ['entry1'] }];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(1);
+      expect(result[0]).toEqual({
+        id: 1,
+        name: 'John',
+        entries: ['entry1'],
+      });
+    });
+
+    it('should handle multiple entries with same comparator value', () => {
+      const input = [
+        { id: 1, entries: ['a'] },
+        { id: 1, entries: ['b'] },
+        { id: 1, entries: ['c'] },
+        { id: 1, entries: ['d'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(1);
+      expect(result[0].entries).toEqual(['a', 'b', 'c', 'd']);
+    });
+  });
+
+  describe('different comparator attributes', () => {
+    it('should work with string comparator attribute', () => {
+      const input = [
+        { name: 'Product A', category: 'Electronics', entries: ['item1'] },
+        { name: 'Product B', category: 'Books', entries: ['item2'] },
+        { name: 'Product C', category: 'Electronics', entries: ['item3'] },
+      ];
+
+      const result = aggregate(input, 'category', 'entries');
+
+      expect(result).toHaveLength(2);
+      expect(result[0]).toEqual({
+        name: 'Product A',
+        category: 'Electronics',
+        entries: ['item1', 'item3'],
+      });
+      expect(result[1]).toEqual({
+        name: 'Product B',
+        category: 'Books',
+        entries: ['item2'],
+      });
+    });
+
+    it('should not aggregate items with undefined comparator values', () => {
+      const input = [
+        { id: undefined, entries: ['a'] },
+        { id: 1, entries: ['b'] },
+        { id: undefined, entries: ['c'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(3);
+      // Items with undefined id are NOT aggregated - each remains separate
+      expect(result[0].entries).toEqual(['a']);
+      expect(result[1].entries).toEqual(['b']);
+      expect(result[2].entries).toEqual(['c']);
+    });
+
+    it('should handle null comparator values separately', () => {
+      const input = [
+        { id: null, entries: ['a'] },
+        { id: 1, entries: ['b'] },
+        { id: null, entries: ['c'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(3);
+      expect(result[0].entries).toEqual(['a']);
+      expect(result[1].entries).toEqual(['b']);
+      expect(result[2].entries).toEqual(['c']);
+    });
+
+    it('should not aggregate items missing the comparatorAttr property', () => {
+      const input = [
+        { id: 1, entries: ['a'] },
+        { name: 'No ID', entries: ['b'] }, // missing 'id' property
+        { id: 1, entries: ['c'] },
+        { entries: ['d'] }, // also missing 'id' property
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      // 3 entries: aggregated id:1, and two separate items without 'id' property
+      expect(result).toHaveLength(3);
+      // Items with id: 1 are aggregated
+      expect(result[0]).toEqual({ id: 1, entries: ['a', 'c'] });
+      // Items missing 'id' are NOT aggregated - each remains separate
+      expect(result[1]).toEqual({ name: 'No ID', entries: ['b'] });
+      expect(result[2]).toEqual({ entries: ['d'] });
+    });
+  });
+
+  describe('different group attributes', () => {
+    it('should work with different groupOn attribute name', () => {
+      const input = [
+        { id: 1, items: ['item1'] },
+        { id: 1, items: ['item2'] },
+        { id: 2, items: ['item3'] },
+      ];
+
+      const result = aggregate(input, 'id', 'items');
+
+      expect(result).toHaveLength(2);
+      expect(result[0].items).toEqual(['item1', 'item2']);
+      expect(result[1].items).toEqual(['item3']);
+    });
+  });
+
+  describe('complex entries', () => {
+    it('should aggregate entries containing objects', () => {
+      const input = [
+        { invoiceId: 'INV-001', entries: [{ itemId: 1, quantity: 2 }] },
+        { invoiceId: 'INV-002', entries: [{ itemId: 2, quantity: 1 }] },
+        { invoiceId: 'INV-001', entries: [{ itemId: 3, quantity: 5 }] },
+      ];
+
+      const result = aggregate(input, 'invoiceId', 'entries');
+
+      expect(result).toHaveLength(2);
+      expect(result[0].entries).toEqual([
+        { itemId: 1, quantity: 2 },
+        { itemId: 3, quantity: 5 },
+      ]);
+      expect(result[1].entries).toEqual([{ itemId: 2, quantity: 1 }]);
+    });
+
+    it('should aggregate entries with multiple items in each entry', () => {
+      const input = [
+        { id: 1, entries: ['a', 'b'] },
+        { id: 1, entries: ['c', 'd'] },
+        { id: 2, entries: ['e'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(2);
+      expect(result[0].entries).toEqual(['a', 'b', 'c', 'd']);
+      expect(result[1].entries).toEqual(['e']);
+    });
+  });
+
+  describe('numeric comparator values', () => {
+    it('should correctly compare numeric values', () => {
+      const input = [
+        { id: 1, entries: ['a'] },
+        { id: 2, entries: ['b'] },
+        { id: 1, entries: ['c'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(2);
+      expect(result.find((r) => r.id === 1).entries).toEqual(['a', 'c']);
+      expect(result.find((r) => r.id === 2).entries).toEqual(['b']);
+    });
+
+    it('should treat 0 as a valid comparator value', () => {
+      const input = [
+        { id: 0, entries: ['a'] },
+        { id: 1, entries: ['b'] },
+        { id: 0, entries: ['c'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(2);
+      expect(result[0].entries).toEqual(['a', 'c']);
+      expect(result[1].entries).toEqual(['b']);
+    });
+  });
+
+  describe('preserving other properties', () => {
+    it('should preserve all properties from the first matching entry', () => {
+      const input = [
+        { id: 1, name: 'First', extra: 'data1', entries: ['a'] },
+        { id: 1, name: 'Second', extra: 'data2', entries: ['b'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(1);
+      expect(result[0].name).toBe('First');
+      expect(result[0].extra).toBe('data1');
+      expect(result[0].entries).toEqual(['a', 'b']);
+    });
+  });
+
+  describe('empty entries arrays', () => {
+    it('should handle empty entries arrays', () => {
+      const input = [
+        { id: 1, entries: [] },
+        { id: 1, entries: ['a'] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(1);
+      expect(result[0].entries).toEqual(['a']);
+    });
+
+    it('should handle all empty entries arrays', () => {
+      const input = [
+        { id: 1, entries: [] },
+        { id: 1, entries: [] },
+      ];
+
+      const result = aggregate(input, 'id', 'entries');
+
+      expect(result).toHaveLength(1);
+      expect(result[0].entries).toEqual([]);
+    });
+  });
+});
+
diff --git a/packages/server/src/modules/Import/_utils.ts b/packages/server/src/modules/Import/_utils.ts
index d30d85ee8..e9e836c42 100644
--- a/packages/server/src/modules/Import/_utils.ts
+++ b/packages/server/src/modules/Import/_utils.ts
@@ -284,9 +284,11 @@ export const getResourceColumns = (resourceColumns: {
   return R.compose(transformInputToGroupedFields, mapColumns)(resourceColumns);
 };
 
+export type ModelResolver = (modelName: string) => any;
+
 // Prases the given object value based on the field key type.
 export const valueParser =
-  (fields: ResourceMetaFieldsMap, tenantModels: any, trx?: Knex.Transaction) =>
+  (fields: ResourceMetaFieldsMap, modelResolver: ModelResolver, trx?: Knex.Transaction) =>
     async (value: any, key: string, group = '') => {
       let _value = value;
 
@@ -308,7 +310,7 @@ export const valueParser =
         _value = multiNumberParse(value);
         // Parses the relation value.
       } else if (field.fieldType === 'relation') {
-        const RelationModel = tenantModels[field.relationModel];
+        const RelationModel = modelResolver(field.relationModel);
 
         if (!RelationModel) {
           throw new Error(`The relation model of ${key} field is not exist.`);
@@ -325,7 +327,7 @@ export const valueParser =
         _value = get(result, 'id');
       } else if (field.fieldType === 'collection') {
         const ObjectFieldKey = key.includes('.') ? key.split('.')[1] : key;
-        const _valueParser = valueParser(fields, tenantModels);
+        const _valueParser = valueParser(fields, modelResolver);
         _value = await _valueParser(value, ObjectFieldKey, fieldKey);
       }
       return _value;
@@ -402,12 +404,17 @@ export function aggregate(
   groupOn: string,
 ): Array<Record<string, any>> {
   return input.reduce((acc, curr) => {
+    // Skip aggregation if the current item doesn't have the comparator attribute
+    if (curr[comparatorAttr] === undefined || curr[comparatorAttr] === null) {
+      acc.push({ ...curr });
+      return acc;
+    }
     const existingEntry = acc.find(
       (entry) => entry[comparatorAttr] === curr[comparatorAttr],
     );
 
     if (existingEntry) {
-      existingEntry[groupOn].push(...curr.entries);
+      existingEntry[groupOn].push(...curr[groupOn]);
     } else {
       acc.push({ ...curr });
     }